Between 2002-2006, the prospective Chronic Renal Insufficiency Cohort (CRIC) Study enrolled 3612 adults with chronic kidney disease to address overarching goals to identify predictors of rapid progression of kidney disease and evaluate the relationship between kidney dysfunction and the risks of subclinical and clinical cardiovascular events, death, and resource utilization through an initial 5-year follow-up. The proposed Phase 2 of CRIC, which extends follow-up through 2013, offers a unique opportunity to leverage the existing effort and success of CRIC to establish a cohort of participants with chronic kidney disease who have long-term prospective follow-up on progression of kidney disease and a variety of different outcomes. This unparalleled resource will also expand the science related to chronic kidney disease natural history as well as the impact on cardiovascular disease and other adverse events. Specific Aims of our clinical center in Phase 2 of the CRIC are: 1. To re-enroll a high percentage of CRIC Phase 1 participants into Phase 2 of CRIC 2. To collect exposure and outcome data per the CRIC Phase 1 and 2 protocols 3. To maintain high levels of retention in the study 4. To investigate self-reported clinical events and obtain supporting medical records and documentation. 5. To enter data and process/ship biological specimens. 6. To implement local quality assurance and quality control procedures as a means to obtain standardized, high quality measurements 7. To monitor data collection, data entry, and follow-up rates 8. To participate in governance and oversight of the CRIC study through studywide subcommittees and activities 9. To publish and present findings from the CRIC Study 10. To promote and support the conduct of ancillary studies in CRIC, including collaboration with the broader nephrology research community.